Transportation Safety Board of Canada investigator Isabelle Langevin examines a plane that landed on the roof of Promenades St-Bruno after colliding with another plane on March 17, 2017.Transportation Safety Board of Canada

A student pilot at Cargair Aviation who had not reported his or her location forced air traffic controllers at Trudeau airport to abort the descent of a Porter Airlines flight last year, Transport Canada records show.

The incident is one of several communication problems involving Cargair flights recorded over the past year in Transport Canada’s Civil Aviation Daily Occurrence Reporting System (CADORS), which tracks incidents that could affect aviation safety.

Two men studying at Cargair to be pilots for Chinese airlines crashed their Cessna planes in mid-air over St-Bruno March 17. One pilot died. Seconds before the crash, one of the pilots did not respond to four attempts to contact him by an air traffic controller at St-Hubert Airport.

Before the March 17 crash, the most serious reported incident involving Cargair over the past year appears to have been one that occurred on July 5, 2016.

A Cargair Cessna aircraft “flew over Laval at 2,000 feet without contacting Dorval tower or the Montreal terminal about its departure from St-Hubert Airport,” the CADORS report said. “No radio contact.”

Air traffic controllers told the pilot of a Porter Airlines de Havilland turbo-prop aircraft to abort its descent into Trudeau airport in Dorval. The Porter flight was told to keep its altitude at 3,000 feet “to maintain distance from the other aircraft,” the report said.

In an update posted two months later, a civil aviation safety inspector reported that after the incident “there was a meeting between the instructor and the student. All the flight phases were reviewed to ensure that the student understood the nature of the events that had occurred.”

On Monday, Cargair said no one was available to comment. But in an emailed statement, the company told the Montreal Gazette the Trudeau airport episode was an isolated incident.

“In the very rare cases where something like this happens, we get the details quickly and once the pilot lands, we meet them to go over every phase of the flight to make sure the pilot knows his position at all times.”

First responders at the Promenades St-Bruno shopping centre March 17 after a one of the two airplanes involved in a mid-air collision crashed onto the parking lot. Pierre Obendrauf / Montreal Gazette

Edward McKeogh, a pilot who is president of Canadian Aviation Safety Consultants, said student pilots should avoid the Dorval area “like the plague.”

A pilot would only end up close to a major airport without alerting the tower “if they’re not well instructed, or they’re not thinking well, or if they’re not looking,” McKeogh said.

“On a clear day, you can see Dorval from St-Hubert, and there’s no reason to miss all those runways and hangars. You just steer clear of anything like that.”

Aircraft landing at and taking off from Trudeau “take up a lot of vertical space,” McKeogh said. On take-off, for example, “they’ll whip right up through 1,000 and 2,000 feet very, very quickly as they’re on their way to 40,000.”

Cargair, which describes itself as Canada’s largest private pilot school, instructs about 150 pilots every year for airlines in China, where training facilities can’t keep up with demand. The company owns 60 planes used for training.

The CADORS database indicates that on at least 14 occasions over the past year, Cargair pilots reported radio failures during flights.

Fourteen communication errors involving Cargair were also cited in the CADORS system. For example, in May 2016, a Cargair Cessna “took off without authorization when the tower had only asked it to line up.”

In its statement, Cargair said because it is based at the busy St-Hubert airport, incidents involving its planes are more likely to end up in the CADORS system than those involving planes owned by companies at private airports or in areas without air-traffic control towers.

The company said its planes are flown about 25,000 hours per year.

Cargair’s operations manager has previously said the company didn’t think mechanical problems, the weather or language barriers were factors.

The nationality of the pilots involved in the Cargair incidents is not indicated in CADORS.

Cargair says Chinese student pilots must be proficient in English to attend the school. They are taught in English and communicate with air-traffic control towers in English, the company says.

An aviation school that teaches Chinese students in Northern Ontario recently told a local newspaper that “the students arrive with a basic English level and we teach them aviation English.”

The preliminary incident report about the March 17 crash notes that one of the students was supposed to stay at 1,500 feet, while the other was instructed to increase his altitude to 1,100 feet. It’s unclear which pilot did not follow directions.

The Transportation Safety Board of Canada is investigating the St-Bruno crash. A spokesperson said it’s unclear how long the investigation will take.